Vantaggi
I worked at Kantar just out of college. It is a great place to gain market research industry experience and be exposed to some really smart people. Everyone I came in contact with was incredibly kind and casual. I would recommend working here for 1 -2 years tops to garner experience and learn.
Svantaggi
That being said, by the time I left Kantar I realized I was making 20-40% less than some of my coworkers, even some that started after me. Management is so top heavy due to the size of the org that it is impossible to get anything done, and the turnover is *incredibly* high here. All teams were consistently very understaffed for the almost 4 years that I worked there. No bonuses, rarely a positive business outlook, and most importantly, almost no opportunities for growth or salary increase. You will continue to wear more and more hats with no sign of any kind of compensation or promotion, which leads to burnout.